Water form gear removal

[Lukew]

The shinohara runs the following dampening system
Chrome roller in the fount water tray picks up the water
Metering roller is high up on the chrome roller and meters the amount of fount that makes it through the nip
Water form roller goes onto the chrome roller when water forms go onto the plate.

Chrome roller & metering roller are geared together
Water form roller has a separate gear & is geared to run at the same speed as the plate cylinder

This is a water roller system that some other manufacturers use also. I am wondering if anyone has taken the gear off the water form roller and allowed it to be driven by the chrome roller, effectively spinning at the same speed as the chrome & metering roller?
Do you think this will happen, or will the plate cylinder take over and make the water form spin at the same speed as the plate?

I am thinking of giving it a go on Monday, the reason for wanting the water form to spin at the same speed as the chrome roller is we get water beading/ building up between the chrome roller & the water form roller on start up. Once you hit damp on button with in 3 - 5 seconds water starts building up between this point. I'm thinking if the water form & chrome spin at the same speed the fount should pass through the nip more effectively
It doesn't matter what water form to chrome to plate strips are it still happens, nor does it matter what level of alcohol is run.

I know it is a roller hardness or compound issue, but it is the rollers we were recommended by the roller company and there is no chance of a swap now.
Standard starting shore A hardness of the metering roller is meant to be 30
Standard starting shore A hardness of the water form roller is meant be 23

The company has supplied
Westland IPA free compound metering roller 25 shore A hardness
Katsura standard compound water form roller 27 shore A hardness

I believe that both roller compounds need to be the same so that the water passes through the nip the same. As it stands you have one roller that allows the fount to pass through the nip effectively and one not so effectively, plus the fact that the water form roller is spinning at a significantly reduced rate then the chrome on start up leading to the fount building up between the nip.

I have read through the Komori picture framing thread and there is talk about removing the gear from the water form on that press but there are no comments about what will end up driving the water form, be it the plate cylinder or the water roller system through nip pressure.

Any thoughts on the outcome?

 

[john beniston]

I think if you remove the gear the water form roller will be driven by the plate not the chrome roller.
Being driven by the plate, whether it is a water form or an ink form roller is very bad.
How do you know that the ink beading you describe is not normal?
I would think that if the water is beading up on the "pick up side" of the nip the it would indicate that the relatively thick film on that side is being properly metered. Are you having any other problems with your dampening apart from the one described.
Finally what do Shinohara have to say about it.
I would not take off the gear, the engineers who designed your press, determined that it should be on there. It is not there for fun.
How about positive drive through the gap or prevention of skidding when the non driven, slowed down, roller contacts the leading edge.

 

[Lukew]

No the fount water shouldn't build up between the chrome & water form, well not so quickly anyway.
I guess I was thinking that if the ink rollers can be driven by the oscillator rollers & not the plate if the stipe is heavier to the oscillator then the plate. Then the same would happen for the water form roller.

I have a feeling that the QM heildelberg drives the water form from the chrome roller without a gear, but perhaps I'm wrong.

If the plate is going to drive the water form roller then it is of no benefit of removing the gear.

 

[Lukew]

Gave it a go today, didn't work!!! Water form still gets driven by the plate and stops spinning at the plate cylinder cut out.. I guess I failed to think about the slippage between the chrome and water form due to the fountain solution film.

Was near positive the Qm held ran without a geared water form.

 

[Kaoticor]

Thanks for posting that info

 

[white rabbit]

Gave it a go today, didn't work!!! Water form still gets driven by the plate and stops spinning at the plate cylinder cut out.. I guess I failed to think about the slippage between the chrome and water form due to the fountain solution film.

Was near positive the Qm held ran without a geared water form.

QM does run without a gear on the damp form, but the stripe to the pan roller is roughly twice the plate stripe.

Just FYI...

 

[Alois Senefelder]

Gear Driven Compliant Rollers

Gear Driven Compliant Rollers

Hello fellow Lithographers,


Plate Dampeners have been run Gear Free successfully since Ira Rubel/Casper Hermann

introduced the Offset Press in 1906; this includes Molleton/Bare Back Rollers on sheet-fed and

Web presses, squeeze type dampening systems were only introduced during the late 1960/70s



A PDF that I hope will be of interest and value


http://Gearing or not to Gear, that is the question




Regards, Alois

 

[Al Ferrari]

Alois,

Your pdf link does not work on Safari.

Al

 

[Dan Roll]

Removing the gear driving the form roller on the three roller system used on the Sakuri and removing the gear from the form roller on the KomoriMatic dampener used on Komoris accomplishes two very different things. On the Komori, it allows the form roller to turn at the oscillator speed, rather than the gear speed. On the three roller dampener removing the gear allows the roller to turn at the plate speed when in contact with the plate and then when the gap comes around, at the speed of whatever other roller the form is set tightest too. This rapid change of speed, twice for each revolution of the press, is problematic to say the least.

 

[Alois Senefelder]

The Mechanics of Fluid Transportation

The Mechanics of Fluid Transportation

Hello fellow Lithographers,


Fundamentals

The Inking/Dampening Systems of Offset Lithographic Printing Presses are fluid transportation systems.

All plate inkers and plate dampeners also the vibrator rollers must rotate at a circumferential speed

equal to that of the plate cylinder.


Regards, Alois

 

[Alois Senefelder]

******

******

FAO - Al Ferrari


The Link -Gearing or not to Gear, that is the question


Regards, Alois

 

[Alois Senefelder]

*****

*****

FAO - Al Ferrari,


try this one - : Komori picture framing

 

[Lukew]

Removing the gear driving the form roller on the three roller system used on the Sakuri and removing the gear from the form roller on the KomoriMatic dampener used on Komoris accomplishes two very different things. On the Komori, it allows the form roller to turn at the oscillator speed, rather than the gear speed. On the three roller dampener removing the gear allows the roller to turn at the plate speed when in contact with the plate and then when the gap comes around, at the speed of whatever other roller the form is set tightest too. This rapid change of speed, twice for each revolution of the press, is problematic to say the least.

Yeah Dan thats what I found once I removed the gear. The shino runs the same roller layout as the sakuri.
I guess the issue we are having comes down to the wrong shore A hardness & compound.
Next time we will use both bottcher water form & metering roller.
Interesting westland does manufacture the wero aqua metering roller in 22 / 25 / 30 shore hardness range. Issue is the supplier here only stocks the 25 shore A version.

 

[Al Ferrari]

FAO - Al Ferrari,


try this one - : Komori picture framing

Still no good.

 

[Al Ferrari]

FAO - Al Ferrari


The Link -Gearing or not to Gear, that is the question


Regards, Alois

Still no good.

Al

 

[Alois Senefelder]

!!!!!!

!!!!!!

FAO Al Ferrari,


If at first you don't succeed try again !




Thread: Komori picture framing



Regards, Alois

 

[Dan Roll]

I have never had a lot of luck with this particular dampener design. Many versions use a bracket design that increases the pressure from the chrome (or ceramic) roller to the form roller significantly when the dampener engages. Too much pressure at this point causes great difficulties for running without alcohol and my attempts to reduce this pressure to a moderate one when the press was running led to a gap between these two rollers when the press stopped, allowing water from the first unit to drip onto the register board. Other than the dampener design, a nice little press.

 

[Al Ferrari]

Safari screen shot of your link

Safari screen shot of your link

here is what I see:




[Edit]: Is anyone having success viewing these links from Alois???

 

[Deleted member 16349]

here is what I see:




[Edit]: Is anyone having success viewing these links from Alois???

I don't see them either. Would like to.

 

[Al Ferrari]

Thanks Erik,

What browser are you using?

Al